Elle was asked to find the missing measure of an interior angle of a heptagon. A heptagon has angles x, 116 degrees, 115 degrees, 155 degrees, 138 degrees, 95 degrees, and 150 degrees. Elle’s work is shown below. Steps Elle’s Work Step 1 (n minus 2) 180 degrees = (7 minus 2) 180 degrees = 900 degrees Step 2 900 minus (116 + 115 + 155 + 138 + 150) Step 3 x = 226 degrees Where, if at all, did Elle first make a mistake finding the measure of an interior angle? step 1 step 2 step 3 Elle did not make a mistake.